It is a new estimate of insect species worldwide. It reveals that there could be between 8 and 14 million more species than previously believed. Few of them have been discovered, according to findings from Cornell University (United States). The study appears in 'Proceedings of the National Academy of Sciences'. We would have a total of 20 million species of insects
Most experts currently accept an estimate of about 6 million insect species. It is an assessment that has been maintained for the last 40 years. The new count used genetic information from 1.6 million individual tropical insects. But a census of a very diverse group of parasitoid wasps in Costa Rica and statistical strategies estimate that there are 14 to 20 million.
This has profound implications for understanding the scale, richness and future of biodiversity on Earth. «We cannot protect species if we do not know they exist. In order to understand the biodiversity of our planet, it is important to know how many there are," they indicate.
About 1.2 million species of insects have been described so far. «There are still many to discover. The more we sample, the more we discover," they point out. "It's about trying to estimate what is not observed based on what we know."
The great diversity of insects is due to several reasons. Many undergo metamorphosis during their life cycle. It allows them to exploit different habitats depending on their stage of development. For example, caterpillars feed on plants in their early stages. When they become butterflies or moths, they feed mainly on the nectar of flowers. Additionally, most insects are small, allowing them to maintain populations in very restricted areas.
Intensive insect sampling was carried out in the Guanacaste Conservation Area (ACG). It is a protected area of 169,000 hectares in northwest Costa Rica. They captured more than 1.6 million insect specimens, all of them marked with barcodes (a technique that involves sequencing a small segment of DNA to determine unique species).
Proportions
The team used statistical techniques to determine the ratio between the number of wasps detected and the number of wasps that were potentially not detected. This proportion was applied to the total number of insects. They also estimated how many species of insects exist worldwide. They determined the proportion of estimated tree species globally (about 73,000) compared to the estimated number of tree species in the Anatolian Forest (1,200-1,500).
It is estimated that there are 20 million species of insects. "There are a large number of undescribed insects, those without names," they point out. "With recent reports of declining insect populations, there could be many species in decline that we haven't even discovered."
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